NORTH AMERICAN EARLY TERTIARY BRYOZOA. 155 



l distribution. Priabonian of Vicentin (Waters) ; Helvetian of Tou- 

 raine (collection Canu). 



Plesiotypcs.Cat. No. 639-27, U.S.N.M. 



CALLOPORA VICINA, new species. 



Plate 81, figs. 2, 3. 



Description. The zoarium incrusts bryozoa. The zooecia are elongated, dis- 

 tinct, elliptical, or oval; the mural rim is quite salient, flat, very finely granular. 

 The opesium is of the same form as the zooecium. The avicnlaria are distributed 

 irregularly over the zoarium between the opesia; they are oblique and their an- 

 terior part is embedded in the mural rim, whereas their point projects considerably 

 above the latter. 



,, ~ . \ho=O.BO mm. . \Lz=QAO mm. 



Measurements. Opesia 7 . , Zooecia , n nn 



tfo=0.16 mm. lfe=0.26 mm. 



Variations. The mural rim is rarely regular; more often it is a little enlarged 

 at the base. The avicularia often exhibit two lateral denticles serving as a pivot 

 for the mandible which can thus easily be placed between the mural rims, which 

 are always separated by a deep furrow. On our specimens there are numerous 

 zooecia with double mural rims, which have undergone total regeneration. 



Affinities. This species is really close to Callopora tenuirostris Hincks, 1880, 

 but differs from it in its much smaller avicularia. It appears to be intermediate 

 between the CaUopora lineata group and the C. tenuirostris group. 



Occurrence. Vicksburgian ("Chimney rock" of Marianna limestone 1 ): One 

 mile north of Monroeville, Alabama (common). 



Cotypes.C&t. No. 64234, U.S.N.M. 



CALLOPORA (?) TUBEROSA, new species. 



Plate 3, fig. 14. 



Description. -The zoarium is free, unilamellar. The zooecia are little, distinct, 

 subcircular; the mural rim is salient, very thick, convex, and bears 6 to 8 large 

 tuberosities entire or hollow. The opesium is oval, a little crenulated. The ovicell 

 is hyperstomial. On the gymnocyst there are one or two large, projecting avicularia 

 in which the orifice, turned toward the opesium, is perpendicular to the zooecial 

 plane and consequently hardly visible. Between the zooecia there are long, thin 

 avicularia without a pivot. 



Affinities. This species is quite an unusual form and we have been unable to 

 make a detailed study of it because the figured specimen is the only one known. 

 Some of the interzooecial avicularia have a resemblance to Holopordla (Jecostilxi! 

 Audouin, 1826, but are provided with a pivot. 



Occurrence. Midwayan (Clayton limestone) : One mile west of Fort Gaines. 

 Georgia (very rare). 



Holotype.GBk. No. 63792. U.S.N.M. 



